The invention relates to a clamping apparatus for joining two flanges which includes clamping members disposed circumferentially around the flanges and engaging the flanges at their outer ends for axial compression of the flanges.
The apparatus according to the invention is designed for use with pipes of relatively large diameters (1 m and even larger) and for pressures of at least 80 bar. The apparatus utilized so far with only one tensioning element are not suitable for use in connection with large diameter pipes and with large pressures since, due to the design of these apparatus, the clamping forces cannot be accurately determined.
German Pat. No. 3,048,903 discloses a clamping apparatus for connecting two flanges by way of clamping members which are spaced circumferentially around the flanges and have inner grooves receiving the outer edges of the flanges and around which a clamping chain extends for forcing the clamping members inwardly into firmer engagement with the flanges. In this arrangement the chain links are positively connected to the clamping members such that there are relatively high frictional forces in the chain. There are also high frictional forces between the clamping members and the flanges as a result of their positive engagement with the chain which generates relative movement between the clamping members and the flanges. With this arrangement only the clamping members adjacent the chain tightener will be forced to perform the desired radial clamping movement.
Based on this state of the art it is the principal object of the present invention to provide a remotely operable clamping apparatus in which the clamping members are operable with only a minimum of friction while they are moved radially without being subject to any additional frictional forces as a result of the clamping action. The clamping apparatus should be suitable for use with large diameter pipes and for high pressures and it should be remotely operable in a simple manner.